Transmitter and method for transmitting data block in wireless communication system

ABSTRACT

Provided are a transmitter and a method for transmitting a data block in a wireless communication system. The method comprises the following steps: encoding an information bit and generating a block coded with an NCBPSS bit; generating two sub-blocks by parsing the coded block; and transmitting the two sub-blocks to the transmitter. By preventing the bits that are contiguous to the encoding block from having continuous identical reliabilities on a signal constellation, the deterioration of the decoding performance of the transmitter can be prevented.

CROSS-REFERENCES

The present application is a continuation of U.S. patent applicationSer. No. 13/749,582, filed on Jan. 24, 2013, which is a continuation ofU.S. patent application Ser. No. 13/591,113, filed on Aug. 21, 2012,which is a continuation of PCT/KR2011/007903, filed on Oct. 21, 2011,which claims priority of Korean Patent Application Number10-2010-0103381, filed on Oct. 22, 2010, Korean Patent ApplicationNumber 10-2010-0110160, filed on Nov. 8, 2010, and Korean PatentApplication Number 10-2011-0107646, filed on Oct. 20, 2011, which areincorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to wireless communication, and moreparticularly, to a method of transmitting a data block in a wirelesscommunication system, and a transmitter.

BACKGROUND ART

Recently, various wireless communication technologies are underdevelopment in accordance with the advancement of informationcommunication technology. Among them, a wireless local area network(WLAN) is a technique allowing mobile terminals such as personal digitalassistants (PDAs), lap top computers, portable multimedia players(PMPs), and the like, to wirelessly access the Internet at homes, inoffices, or in a particular service providing area, based on a radiofrequency technology.

As a technology specification that has been relatively recentlylegislated in order to overcome a limitation in a communication speedthat has been pointed out as a weak point in the WLAN, there is the IEEE(Institute of Electrical and Electronics Engineers) 802.11n. An objectof the IEEE 802.11n is to increase a speed and reliability of a wirelessnetwork and extend an operating distance of the wireless network. Morespecifically, the IEEE 802.11n is based on multiple inputs and multipleoutputs (MIMO) technology in which multiple antennas are used at both ofa transmitting end and a receiving end in order to support a highthroughput (HT) having a maximum data processing speed of 540 Mbps ormore, minimize a transmission error, and optimize a data speed. Further,in this specification, a coding scheme of transmitting severaloverlapped duplicates may be used in order to increase data reliability,and an orthogonal frequency division multiplexing (OFDM) scheme may alsobe used in order to increase a speed.

In the wireless communication system, codewords are generallyinterleaved over the entire frequency band in order to obtain afrequency diversity gain and maximize an interleaving effect. When asize of a used frequency band increases, a coding gain and a diversitygain are obtained by increasing a codeword and an interleaver to thesize of the frequency band.

However, when the size of the interleaver is increased in accordancewith an increase in size of the frequency band, a burden on changing anexisting structure and complexity may increase.

DISCLOSURE Technical Problem

The present invention provides a method of transmitting a data blockcapable of supporting a broadband in a wireless local area networksystem, and a transmitter.

Technical Solution

In an aspect, a method of transmitting a data block in a wirelesscommunication system is provided. The method includes encodinginformation bits to generate a coded block of N_(CBPSS) bits, parsingthe coded block to generate two subblocks with index l=0, 1, andtransmitting the two subblocks to a receiver. The coded block is parsedas shown:

${y_{k,l} = x_{{2{s \cdot N_{ES}}{\lfloor\frac{k}{s \cdot N_{ES}}\rfloor}} + {l \cdot s \cdot N_{ES}} + {k\mspace{11mu}{{mod}{({s \cdot N_{ES}})}}}}},{k = 0},1,\ldots\mspace{14mu},{\frac{N_{CBPSS}}{2} - 1}$

where

${s = {\max\left\{ {1,\frac{N_{BPSCS}}{2}} \right\}}},$

N_(BPSCS) is the number of coded bits per subcarrier per spatial stream,

N_(ES) is the number of encoders,

└z┘ is the largest integer less than or equal to z,

z mod t is the remainder resulting from the division of integer z byinteger t,

x_(m) is the m-th bit of a block of bits, m=0 to N_(cBPss)−1, and

y_(k,l) is bit k of the subblock l.

Each of the two subblocks may be interleaved by an interleaver.

The two subblocks may correspond to two frequency bands respectively.

Each of the two frequency bands may have a bandwidth of 80 MHz.

The two frequency bands may be contiguous.

The two frequency bands may not be non-contiguous.

In another aspect, a transmitter of transmitting a data block in awireless communication system is provided. The transmitter includes acoding unit configured to encode information bits to generate a codedblock of N_(CBPSS) bits, a parsing unit configured to parse the codedblock to generate two subblocks with index l=0, 1, and a transmissionunit configured to transmit the two subblocks to a receiver. The parsingunit is configured to parse the coded block as shown above.

In still another aspect, a method of transmitting a data block in awireless communication system is provided. The method includesgenerating a coded block of N_(CBPSS) bits, parsing the coded block togenerate two subblocks with index l=0, 1, and transmitting the twosubblocks to a receiver. The coded block is parsed as shown:

$y_{k,l} = \left\{ \begin{matrix}{x_{{2{s \cdot N_{ES}}{\lfloor\frac{k}{s \cdot N_{ES}}\rfloor}} + {l \cdot s \cdot N_{ES}} + {k\mspace{11mu}{{mod}{({s \cdot N_{ES}})}}}},} \\{{k = 0},1,\ldots\mspace{14mu},{{\left\lfloor {N_{CBPSS}/\left( {2{s \cdot N_{ES}}} \right)} \right\rfloor{s \cdot N_{ES}}} - 1}} \\{x_{{2{s \cdot N_{ES}}{\lfloor\frac{k}{s \cdot N_{ES}}\rfloor}} + {2{s \cdot {\lfloor\frac{k\;{{mod}{({s \cdot N_{ES}})}}}{s}\rfloor}}} + {k\;{mod}\; s}},} \\{{k = {\left\lfloor \mspace{11mu}{N_{CBPSS}/\left( {2{s \cdot N_{ES}}} \right)} \right\rfloor{s \cdot N_{ES}}}},\ldots\mspace{14mu},{\frac{N_{CBPSS}}{2} - 1}}\end{matrix} \right.$

In still another aspect, a method of transmitting a data block in awireless communication system is provided. The method includesdetermining a number of bits assigned to a single axis of a signalconstellation, s, and a number of encoders, N_(ES), encoding informationbits to generate a coded block of N_(CBPSS) bits based on s and N_(ES),parsing the coded block to generate a plurality of frequency subblocksbased on s and N_(ES), and transmitting the plurality of frequencysubblocks to a receiver.

In still another aspect, a method of transmitting a data block in awireless communication system is provided. The method includesdetermining a number of bits assigned to a single axis of a signalconstellation, s, and a number of encoders, N_(ES), generating a codedblock, parsing the coded block to generate a plurality of frequencysubblocks in unit of sN_(ES) bits, and transmitting the plurality offrequency subblocks to a receiver.

Advantageous Effects

It is possible to prevent decoding performance of a receiver from beingdeteriorated by allowing contiguous bits of an encoding block not tocontinuously have the same reliability on a signal constellation.

DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing an architecture of the IEEE 802.11.

FIG. 2 is a block diagram showing an example of a physical layerconvergence procedure (PLCP) protocol data unit (PPDU) format.

FIG. 3 is a block diagram showing an example of a transmitter in whichan exemplary embodiment of the present invention is implemented incontiguous bands.

FIG. 4 is a block diagram showing an example of a transmitter in whichthe exemplary embodiment of the present invention is implemented innon-contiguous bands.

FIG. 5 is a diagram showing an example of segment parsing.

FIG. 6 is an example of showing an example in which the segment parsingof FIG. 5 is used.

FIG. 7 is an example showing another example in which the segmentparsing of FIG. 5 is used.

FIG. 8 is a diagram showing an example of segment parsing according tothe exemplary embodiment of the present invention.

FIG. 9 is a diagram showing another example of segment parsing accordingto the exemplary embodiment of the present invention.

FIG. 10 is a diagram showing segment parsing according to the exemplaryembodiment of the present invention.

FIG. 11 is a diagram showing segment parsing according to anotherexemplary embodiment of the present invention.

FIGS. 12 to 14 are diagrams showing simulation results.

FIG. 15 is a flow chart showing a method of transmitting data accordingto the exemplary embodiment of the present invention.

FIG. 16 is a flow chart showing a method of transmitting data accordingto another exemplary embodiment of the present invention.

FIG. 17 is a block diagram showing a transmitter in which the exemplaryembodiment of the present invention is implemented.

MODE FOR INVENTION

A wireless local area network (WLAN) system in which an exemplaryembodiment of the present invention is implemented includes at least onebasic service set (BSS). The BSS is a set of successfully synchronizedstations (STA) in order to perform communication therebetween. The BSSmay be divided into an independent BSS (IBSS) and an infrastructure BSS.

The BSS may include at least one STA and access point (AP). The STA maybe an AP or non-AP STA. The AP is a functional medium connecting theSTAs in the BSS to each other through a wireless medium. The AP may becalled other names such as a centralized controller, a base station(BS), a scheduler, and the like.

FIG. 1 is a diagram showing an architecture of the IEEE 802.11.

The wireless-medium physical layer (PHY) architecture of the IEEE 802.11includes a PHY layer management entity (PLME) layer, that is, a physicallayer convergence procedure (PLCP) sub-layer 110, a physical mediumdependent (PMD) sub-layer 110.

The PLME provides a management function of the PHY in cooperation with amedium access control (MAC) layer management entity (MLME).

The PLCP sub-layer 110 transfers an MAC protocol data unit (MPDU)received from the MAC sub-layer 120 to a PMD sub-layer 100 or transfersa frame coming from the PMD sub-layer 100 to the MAC sub-layer 120according to instruction of the MAC layer, between the MAC sub-layer 120and the PMD sub-layer 100.

The PMD sub-layer 100, which is a lower layer of the PLCP, may allow aPHY entity to be transmitted and received between two STAs through awireless medium.

The MPDU transferred from the MAC sub-layer 120 is called a physicalservice data unit (PSDU) in the PLCP sub-layer 110. The MPDU is similarto the PSDU. However, when an aggregated MPDU (A-MPDU) in which aplurality of MPDUs are aggregated is transferred, individual MPDUs andPSDUs may be different.

The PLCP sub-layer 110 adds an additional field including informationrequired by a physical layer transceiver to the PSDU during a process ofreceiving the PSDU from the MAC sub-layer 120 and transferring the PSDUto the PMD sub-layer 100. Here, the field added to the MPDU may be aPLCP preamble, a PLCP header, tail bits required on a data field, or thelike. The PLCP preamble serves to allow a receiver to prepare asynchronization function and antenna diversity before the PSDU istransmitted. The PLCP header includes a field including information on aframe.

The PLCP sub-layer 110 adds the above-mentioned field to the PSDU togenerate a PLCP protocol data unit (PPDU) and transmit the PPDU to areceiving station through the PMD sub-layer. The receiving stationreceives the PPDU and obtains information required for recovering datafrom the PLCP preamble and the PLCP header to recover the data.

FIG. 2 is a block diagram showing an example of a physical layerconvergence procedure (PLCP) protocol data unit (PPDU) format.

The PPDU 600 may include a legacy-short training field (L-STF) 610, alegacy-long training field (L-LTF) 620, a legacy-signal (L-SIG) field630, a very high throughput (VHT)-SIGA field 640, a VHT-STF 650, aVHT-LTF 660, a VHT-SIGB 670, and a data field 680.

The L-STF 610 is used for frame timing acquisition, automatic gaincontrol (AGC), coarse frequency acquisition, or the like.

The L-LTF 620 is used for channel estimation for demodulation of theL-SIG field 630 and the VHT-SIGA field 640.

The L-SIG field 630 includes control information on a transmission timeof the PPDU.

The VHT-SIGA field 640 includes common information required for the STAssupporting the MIMO transmission to receive a spatial stream. TheVHT-SIGA field 640 includes information on the spatial streams for eachSTA, channel bandwidth information, a group identifier, information onan STA to which each ground identifier is allocated, a short guardinterval (GI), beamforming information (including whether the MIMO isSU-MIMO or MU-MIMO).

The VHT-STF 650 is used to improve performance of AGC estimation in theMIMO transmission.

The VHT-LTE 660 is used for each STA to estimate MIMO channels.

The VHT-SIGB field 670 includes individual control information on eachSTA. The VHT-SIGB field 670 includes information on a modulation andcoding scheme (MCS). A size of the VHT-SIGB field 670 may be changedaccording to a type of MIMO transmission (MU-MIMO or SU-MIMO) and abandwidth of a channel used for transmission the PPDU.

The data field 680 includes the PSDU transferred from the MAC layer, aservice field, tail bits, and pad bits if needed.

In order to support a higher data rate, the WLAN system may supportvarious bandwidths. For example, the bandwidth supported by the WLANsystem may include at least any one of 20 MHz, 40 Hz, 80 MHz, and 160MHz. In addition, since continuous bandwidths may not be always used,non-contiguous bands may be used. For example, a bandwidth of 160 MHz issupported using two non-contiguous 80 MHz bands (represented by 80+80MHz).

Hereinafter, a contiguous 160 MHz band and a non-contiguous 80+80 MHzband will be described by way of example. However, sizes or the numberof bandwidths are not limited.

The WLAN system may support the MU-MIMO and/or the SU-MIMO. Hereinafter,the SU-MIMO will be described by way of example. However, it may beeasily appreciated by those skilled in the art that this description mayalso be to the MU-MIMO.

FIG. 3 is a block diagram showing an example of a transmitter in whichan exemplary embodiment of the present invention is implemented incontiguous bands.

A data unit is encoded by at least one forward error correction (FEC)encoder (S710). The data unit includes PHY pad bits added to the PSDUand scrambled information bits. The data unit may be divided into bitsequences having a specific bit size by an encoder parser, and each ofthe bit sequences may be input to each FEC encoder.

An encoding scheme may be a binary convolution code (BCC). However, adisclosed encoding scheme is only an example, and the scope and spiritof the present invention may be applied to a well-known encoding schemesuch as a low-density parity-check (LDPC), a turbo code, or the like, bythose skilled in the art.

The encoded data units are rearranged into NSS spatial blocks by astream parser (S720). N_(SS) indicates the number of spatial streams.

Output bits of each stream parser are divided into two frequencysubblocks (S730). One frequency subblock may correspond to a bandwidthof 80 MHz.

Each of the two frequency subblocks is independently interleaved by aBCC interleaver (S740). The interleaver may have a size corresponding to20 MHz, 40 MHz, and 80 MHz. Since one frequency subblock corresponds toa 80 MHz band, the frequency subblocks may be interleaved by aninterleaver corresponding to 80 MHz.

Each of the interleaved frequency subblocks is independently mapped ontoa signal constellation by a constellation mapper (S750). The signalconstellation may correspond to various modulation schemes such asbinary phase shift keying (BPSK), quadrature phase-shift keying (QPSK),16-quadrature amplitude modulation (QAM), 64-QAM, or 256-QAM, but is notlimited thereto.

The mapped subblocks are spatially mapped using space-time block coding(STBC) and cyclic shift delay (CSD) (S760).

Two spatially mapped subblocks are subjected to inverse discrete Fouriertransform (IDFT) and then transmitted (S770).

FIG. 4 is a block diagram showing an example of a transmitter in whichthe exemplary embodiment of the present invention is implemented innon-contiguous bands.

In comparison with the transmitter of FIG. 3, each of the two frequencysubblocks is independently subjected to the IDFT. Since each of thefrequency subblocks corresponds to the 80 MHz band and the bandwidth of80 MHz is non-contiguous, each of the two frequency subblocks isindependently subjected to the IDFT.

The segment parser parses the encoded data unit into a plurality offrequency subblocks. This is to support a wider bandwidth withoutincreasing a size of the BCC interleaver.

For example, assume that an existing BCC interleaver supports abandwidth up to 80 MHz. In order to support a bandwidth of 160 MHz, theBCC interleaver cannot but be changed so as to support 160 MHz. However,the data stream is parsed into the subblocks having a size of afrequency bandwidth supported by the BCC interleaver using the segmentparser. Therefore, it is possible to support a wider bandwidth andobtain a frequency diversity gain, without changing a size of theinterleaver.

Hereinafter, the following parameters will be defined.

N_(CBPS): number of coded bits per symbol

N_(CBPSS): number of coded bits per symbol per spatial stream

N_(BPSC): number of coded bits per subcarrier over all spatial streams)

N_(BPSCS): number of coded bits per subcarrier per spatial stream)

N_(SS): number of spatial streams

N_(ES): number of encoders for data field. Here, it is assumed that thenumber of encoders is the same as that of codewords.

R: code rate

FIG. 5 is a diagram showing an example of segment parsing. The existingsuggested simplest segment parsing is to allocate even bits to a firstsubblock and allocate odd bits to a second subblock for each spatialstream.

FIG. 6 is an example of showing an example in which the segment parsingof FIG. 5 is used. In the case of FIG. 6, a modulation scheme is 64-QAM,N_(ES) is 4, N_(ss) is 6, R is 6/5, and a bandwidth is 80 MHz.

The number of bits corresponding to a Q-axis (or an I-axis) of a 64-QAMsignal constellation is 3. Therefore, an output of an encoder isallocated 3-bit by 3-bit in a round robin scheme for each spatialstream. Each spatial stream is parsed by the stream parser to generatesubblocks.

The generated subblocks are interleaved by an interleaver. Interleaverinput bits are sequentially filled in 26 rows, 3j, 3j+1, and 3j+2 rowsof a 3i-th row are mapped to a signal constellation as they are, and 3j,3j+1, and 3j+2 rows of a 3i+1-th row are cyclically shifted downwardlyby a single column and then mapped to the signal constellation. 3j,3j+1, and 3j+2 rows of a 3i+2-th row are cyclic-shifted downwardly bytwo columns and then mapped to the signal constellation.

Under the above-mentioned conditions, continuous bits of a codeword aremapped to positions having different reliabilities on the signalconstellation.

FIG. 7 is an example showing another example in which the segmentparsing of FIG. 5 is used. In the case of FIG. 7, a modulation scheme is64-QAM, N_(ES) is 1 or 2, N_(SS) is 1, R is 6/5, and a bandwidth is 160MHz. Unlike the example of FIG. 6, under these conditions, thecontinuous bits of the codeword are continuously mapped to positionshaving the same reliability on the signal constellation.

When the bits of the codeword continuously have the same reliability onthe signal constellation, decoding performance of a receiver may besignificantly deteriorated. The reason is that when a channel state isdeteriorated in the reliability, an error may occur.

Therefore, the exemplary embodiment of the present invention suggestssegment parsing allowing the bits of the codeword not to continuouslyhave the same reliability on the signal constellation.

In the suggested segment parsing, the number of encoders and the numberof bits allocated to one axis of the signal constellation areconsidered.

The number s of bits allocated to one axis of the signal constellationis considered as follows:

$\begin{matrix}{s = {\max\left\{ {1,\frac{N_{BPSCS}}{2}} \right\}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

For example, when a modulation scheme is BPSK or QPSK, s is 1, when amodulation scheme is 16-QAM, s is 2, when a modulation scheme is 64-QAM,s is 4, and when a modulation scheme is 256-QAM, s is 4.

FIG. 8 is a diagram showing an example of segment parsing according tothe exemplary embodiment of the present invention. FIG. 8 shows anexample in which bits are allocated to two frequency subblocks in an sunit for each of spatial streams according to each modulation scheme.

FIG. 9 is a diagram showing another example of segment parsing accordingto the exemplary embodiment of the present invention. In this example,outputs of each of encoders are bounded. That is, the outputs of theencoders are parsed in an sN_(ES) unit for each of spatial streams.

Contiguous bits of a codeword may be mapped so as to have differentreliabilities on a signal constellation.

The example of FIG. 9 is mathematically shown as follows.

Output bits of each of spatial stream parsers are divided into blocks ofN_(CBPSS) bits. Each of the blocks is parsed into two frequencysubblocks of N_(CBPSS)/2 bits as shown by the following Equation 2:

$\begin{matrix}{\mspace{79mu}{{y_{k,l} = x_{{2{s \cdot N_{ES}}{\lfloor\frac{k}{s \cdot N_{ES}}\rfloor}} + {l \cdot s \cdot N_{ES}} + {k\mspace{11mu}{{mod}{({s \cdot N_{ES}})}}}}},{k = 0},1,\ldots\mspace{14mu},{\frac{N_{CBPSS}}{2} - 1}}} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

where

└z┘ is the largest integer less than or equal to z,

z mod t is the remainder resulting from the division of integer z byinteger t,

x_(m) is the m-th bit of a block of N_(CBPSS) bits (m=0, . . . ,N_(CBPSS)−1),

l is the subblock index, and l=0, 1,

y_(k,1) is the k-th bit of a subblock l.

Meanwhile, when the number of bits of a coded block (that is, the numberof bits of an i-th spatial block) is not a multiple of 2sN_(ES), residuebits that are not allocated to the frequency subblocks may be present.That is, when the number of bits of the coded block is not divided by2sN_(ES), a method of allocating the residue bits is problematic.Typically, the following cases in a bandwidth of 160 MHz areproblematic.

(1) 64-QAM, R=⅔, N_(SS)=5, N_(ES)=5

(2) 64-QAM, R=⅔, N_(SS)=7, N_(ES)=7

(3) 64-QAM, R=¾, N_(SS)=5, N_(ES)=5

(4) 64-QAM, R=¾, N_(SS)=7, N_(ES)=7

FIG. 10 is a diagram showing segment parsing according to the exemplaryembodiment of the present invention.

Bits up to └N_(CBPSS)/(2sN_(ES))┘sN_(ES) are parsed as shown by Equation2. Here, 2sQ (Q=(N_(CBPSS) mod 2sN_(ES))/(2s)) residue bits that are notparsed remain. Then, the residue bits are divided by subsets of s bits.Each of the subsets is allocated to different subblocks in the roundrobin scheme. A first s bit is allocated to a first subblock (l=0). Thatis, a bundle of bits is sequentially allocated to first and secondsubblocks.

That is, when N_(CBPSS) is not divided by 2sN_(ES), each block is parsedinto two frequency subblocks of N_(CBPSS)/2 bits as shown by thefollowing Equation 3:

$\begin{matrix}{y_{k,l} = \left\{ \begin{matrix}{x_{{2{s \cdot N_{ES}}{\lfloor\frac{k}{s \cdot N_{ES}}\rfloor}} + {l \cdot s \cdot N_{ES}} + {k\mspace{11mu}{{mod}{({s \cdot N_{ES}})}}}},} \\{{k = 0},1,\ldots\mspace{14mu},{{\left\lfloor {N_{CBPSS}/\left( {2{s \cdot N_{ES}}} \right)} \right\rfloor{s \cdot N_{ES}}} - 1}} \\{x_{{2{s \cdot N_{ES}}{\lfloor\frac{k}{s \cdot N_{ES}}\rfloor}} + {2{s \cdot {\lfloor\frac{k\;{{mod}{({s \cdot N_{ES}})}}}{s}\rfloor}}} + {k\;{mod}\; s}},} \\{{k = {\left\lfloor \mspace{11mu}{N_{CBPSS}/\left( {2{s \cdot N_{ES}}} \right)} \right\rfloor{s \cdot N_{ES}}}},\ldots\mspace{14mu},{\frac{N_{CBPSS}}{2} - 1}}\end{matrix} \right.} & \left\lbrack {{Equation}\mspace{14mu} 3} \right\rbrack\end{matrix}$

Equation 3 additionally shows allocation of the residue bits in Equation2.

FIG. 11 is a diagram showing segment parsing according to anotherexemplary embodiment of the present invention.

Bits up to └N_(CBPSS)(2sN_(ES))┘sN_(ES) are parsed as shown by Equation2. Then, the residue bits are divided by subsets of 2 bits. Each of thesubsets is allocated to different subblocks in the round robin scheme.

FIGS. 12 to 14 are diagrams showing simulation results. FIG. 12 showssimulation results in a case in which N_(SS) is 3, a modulation schemeis 16-QAM, and R is ½, FIG. 13 shows simulation results in a case inwhich N_(SS) is 3, a modulation scheme is 16-QAM, and R and 3/4, andFIG. 14 shows simulation results in a case in which N_(SS) is 3, amodulation scheme is 256-QAM, and R is ¾. ‘Nseg=1’ indicates that asingle interleaver is used over a bandwidth of 60 MHz without segmentparsing. ‘Nseg=2 and parser=0’ indicate that the existing segmentparsing of FIG. 5 is used. ‘Nseg=2 and parser=1’ indicate that thesuggested segment parsing of FIG. 10 is used.

It is shown that a packet error rate (PER) is increased in the case ofthe existing segment parsing as compared to the case in which thesegment parsing is not performed; however, a PER is not almost increasedin the case of the suggested segment parsing as compared to the case inwhich the segment parsing is not performed.

FIG. 15 is a flow chart showing a method of transmitting data accordingto the exemplary embodiment of the present invention.

Information bits are encoded to generate a coded block (S910). Theencoding may include spatial mapping by a stream parser as well as FECencoding such as BCC or LDPC. The number of bits of a coded block (per aspatial stream) is N_(CBPSS).

The stream parser may perform parsing based on s. Output bits of an FECencoder are rearranged into N_(SS) spatial blocks of N_(CBPSS) bits.Contiguous blocks of s bits may be allocated to different spatialstreams in the round robin scheme.

Segment parsing is performed in a first segment unit (S920). The firstsegment unit may have a value of sN_(ES). Each of the encoded blocks maybe parsed into M frequency subblocks of N_(CBPSS)/M bits. The subblockmay correspond to a bandwidth corresponding to a size of an interleaver.

When M is 2, the encoded block may be parsed to be divided into twosubblocks as shown by Equation 2.

It is determined whether or not residue bits are present (S930).

When N_(CBPSS) is not divided in an M×first segment unit (that is, whenN_(CBPSS) is not a multiple of the M×first segment unit), residue bitsmay be parsed in M frequency subblocks in a second segment unit (S940).The first segment unit N_(ES) is times larger than the second segmentunit, which may have a value of s. When M is 2, the encoded block may beparsed to be divided into two subblocks as shown by Equation 3.

Each of the subblocks is transmitted to a receiver (S950). The parsedsubblocks are independently interleaved by the interleaver, mapped ontoa signal constellation, and then transmitted.

FIG. 16 is a flow chart showing a method of transmitting data accordingto another exemplary embodiment of the present invention.

Information bits are encoded to generate a coded block (S1010). Theencoding may include spatial mapping by a stream parser as well as FECencoding such as BCC or LDPC. The number of bits of a coded block (per aspatial stream) is NCBPSS.

The stream parser may perform parsing based on s. Output bits of an FECencoder are rearranged into N_(CBPSS) bits of N_(SS) spatial blocks.Contiguous blocks of s bits may be allocated to different spatialstreams in the round robin scheme.

Whether or not N_(CBPSS), which is a size of the coded block, is dividedby a reference value is determined (S1020). The reference value may bean M×first segment unit.

When N_(CBPSS) is divided by the M×first segment unit, segment parsingis performed in a first segment unit (S1030). The first segment unit mayhave a value of sN_(ES). Each of the encoded blocks may be parsed intoN_(CBPSS)/M bits of M frequency subblocks. The subblock may correspondto a bandwidth corresponding to a size of an interleaver. When M is 2,the encoded block may be parsed to be divided into two subblocks asshown by Equation 2.

When N_(CBPSS) is not divided by the M×first segment unit, residue bitsmay be parsed into M frequency subblocks in first and second segmentunits (S1040). The first segment unit N_(ES) is times larger than thesecond segment unit. The first segment unit may have a value of sN_(ES),and the second segment unit may have a value of s. The segment parsingis first performed in the first segment unit, and then performed in thesecond segment unit with respect to the residue bits. When M is 2, theencoded block may be parsed to be divided into two subblocks as shown byEquation 3.

Each of the subblocks is transmitted to a receiver (S1050). The parsedsubblocks are independently interleaved by the interleaver, mapped ontoa signal constellation, and then transmitted.

FIG. 17 is a block diagram showing a transmitter in which the exemplaryembodiment of the present invention is implemented. The exemplaryembodiments of FIGS. 15 and 16 may be implemented by the transmitter.

The transmitter 1000 includes a coding unit 1010, a parsing unit 1020,and a transmission unit 1030. The coding unit 1010 may implementfunctions of the FEC encoding and the stream parser of FIGS. 3 and 4.The parsing unit 1020 may implement a function of the segment parser ofFIGS. 3 and 4. The transmission unit 1030 may implement functions of theinterleaver and the constellation mapper of FIGS. 3 and 4.

The coding unit 1010 generates an encoded block. The parsing unit 1020parses the encoded block into a plurality of frequency subblocks. Thesegment parsing Equation 2 or Equation 3 may be implemented by theparsing unit 1020. The transmitting unit 1030 transmits the subblocks toa receiver.

The coding unit 1010, the parsing unit 1020 and the transmission unit1030 may be implemented by one or more processors. The processor mayinclude application-specific integrated circuit (ASIC), other chipset,logic circuit and/or data processing device. The memory may includeread-only memory (ROM), random access memory (RAM), flash memory, memorycard, storage medium and/or other storage device. When the embodimentsare implemented in software, the techniques described herein can beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. The modules can be stored inmemory and executed by processor. The memory can be implemented withinthe processor or external to the processor in which case those can becommunicatively coupled to the processor via various means as is knownin the art.

In view of the exemplary systems described herein, methodologies thatmay be implemented in accordance with the disclosed subject matter havebeen described with reference to several flow diagrams. While forpurposed of simplicity, the methodologies are shown and described as aseries of steps or blocks, it is to be understood and appreciated thatthe claimed subject matter is not limited by the order of the steps orblocks, as some steps may occur in different orders or concurrently withother steps from what is depicted and described herein. Moreover, oneskilled in the art would understand that the steps illustrated in theflow diagram are not exclusive and other steps may be included or one ormore of the steps in the example flow diagram may be deleted withoutaffecting the scope and spirit of the present disclosure.

The invention claimed is:
 1. A method for receiving a data block in awireless communication system, the method comprising: receiving twosubblocks from a transmitter, wherein the two subblocks with index l=0,1 are generated by parsing a coded block of N_(CBPSS) bits as shown:$y_{k,l} = \left\{ \begin{matrix}{x_{{2{s \cdot N_{ES}}{\lfloor\frac{k}{s \cdot N_{ES}}\rfloor}} + {l \cdot s \cdot N_{ES}} + {k\mspace{11mu}{{mod}{({s \cdot N_{ES}})}}}},} \\{{k = 0},1,\ldots\mspace{14mu},{{\left\lfloor {N_{CBPSS}/\left( {2{s \cdot N_{ES}}} \right)} \right\rfloor{s \cdot N_{ES}}} - 1}} \\{x_{{2{s \cdot N_{ES}}{\lfloor\frac{k}{s \cdot N_{ES}}\rfloor}} + {2{s \cdot {\lfloor\frac{k\;{{mod}{({s \cdot N_{ES}})}}}{s}\rfloor}}} + {k\;{mod}\; s}},} \\{{k = {\left\lfloor \mspace{11mu}{N_{CBPSS}/\left( {2{s \cdot N_{ES}}} \right)} \right\rfloor{s \cdot N_{ES}}}},\ldots\mspace{14mu},{\frac{N_{CBPSS}}{2} - 1}}\end{matrix} \right.$ where${s = {\max\left\{ {1,\frac{N_{BPSCS}}{2}} \right\}}},$ N_(BPSCS) is thenumber of coded bits per subcarrier per spatial stream, N_(ES) is thenumber of encoders, └z┘ is the largest integer less than or equal to z,z mod t is the remainder resulting from the division of integer z byinteger t, x_(m) is the m-th bit of a block of bits, m=0 to N_(CBPSS)−1,and y_(k,1) is bit k of the subblock l.
 2. The method of claim 1,wherein N_(CBPSS) is not divisible by 2sN_(ES).
 3. The method of claim2, wherein each of the two subblocks is interleaved by an interleaver.4. The method of claim 3, wherein the two subblocks correspond to twofrequency bands respectively.
 5. The method of claim 4, wherein each ofthe two frequency bands has a bandwidth of 80 MHz.
 6. The method ofclaim 5, wherein the two frequency bands are contiguous.
 7. The methodof claim 5, wherein the two frequency bands are non-contiguous.
 8. Adevice configured for receiving a data block in a wireless communicationsystem, the device comprising: a receiving circuitry configured toreceive two subblocks from a transmitter, wherein the two subblocks withindex l=0, 1 are generated by parsing a coded block of N_(CBPSS) bits asshown: $y_{k,l} = \left\{ \begin{matrix}{x_{{2{s \cdot N_{ES}}{\lfloor\frac{k}{s \cdot N_{ES}}\rfloor}} + {l \cdot s \cdot N_{ES}} + {k\mspace{11mu}{{mod}{({s \cdot N_{ES}})}}}},} \\{{k = 0},1,\ldots\mspace{14mu},{{\left\lfloor {N_{CBPSS}/\left( {2{s \cdot N_{ES}}} \right)} \right\rfloor{s \cdot N_{ES}}} - 1}} \\{x_{{2{s \cdot N_{ES}}{\lfloor\frac{k}{s \cdot N_{ES}}\rfloor}} + {2{s \cdot {\lfloor\frac{k\;{{mod}{({s \cdot N_{ES}})}}}{s}\rfloor}}} + {k\;{mod}\; s}},} \\{{k = {\left\lfloor \mspace{11mu}{N_{CBPSS}/\left( {2{s \cdot N_{ES}}} \right)} \right\rfloor{s \cdot N_{ES}}}},\ldots\mspace{14mu},{\frac{N_{CBPSS}}{2} - 1}}\end{matrix} \right.$ where${s = {\max\left\{ {1,\frac{N_{BPSCS}}{2}} \right\}}},$ N_(BPSCS) is thenumber of coded bits per subcarrier per spatial stream, N_(ES) is thenumber of encoders, └z┘ is the largest integer less than or equal to z,z mod t is the remainder resulting from the division of integer z byinteger t, x_(m) is the m-th bit of a block of bits, m=0 to N_(CBPSS)−1,and y_(k,1) is bit k of the subblock l.
 9. The device of claim 8,wherein N_(CBPSS) is not divisible by 2sN_(ES).
 10. The device of claim9, wherein each of the two subblocks is interleaved by an interleaver.11. The device of claim 10, wherein the two subblocks correspond to twofrequency bands respectively.
 12. The device of claim 11, wherein eachof the two frequency bands has a bandwidth of 80 MHz.
 13. The device ofclaim 12, wherein the two frequency bands are contiguous.
 14. The deviceof claim 12, wherein the two frequency bands are non-contiguous.